RECOVER MAP 3.1.3.14 Trophic Level - Wood Stork and Roseate Spoonbill Nesting Success

Success of nesting for wood storks and roseate spoonbills will be measured as the number of young produced per nest start. This provides at minimum a relative measure that can be compared amoung years. If measured at enough colonies, the absolute number of fledglings produced may be estimated. Historical information exists for this parameter in both species, and techniques for these measurements are standardized in both species (Ogden 1994, Bjork and Powell 1994, Lorenz et al. 2001).

For wood storks, helicopter censuses will be performed at one or more points during the nestling period, and numbers of large, standing young per nest will be counted. This yields young per successful nest. Young per nest start will be calculated by using the total number of estimated starts as the denominator. For roseate spoonbills, the two largest colonies within each sub-region of Florida Bay will be used to estimate nesting success for each group. Survey transects will be established in each of these colonies so that representative samples of nests can be monitored. On the initial visit, 25 to 50 nests will be marked with numbered plastic tags (unless a colony has less than 25 nests, in which case all nests will be marked), and the number of eggs per nest will be counted. Each colony will be visited approximately every ten days, and the contents of each nest will be recorded. Information on clutch size, duration of nesting, reproductive success, and cause of nest failure will be collected for each nest. Nests will be
monitored until failure or until all surviving chicks reach at least 21 days of age. Chicks reaching at least 21 days of age will be considered a successful nesting attempt (fledged). Subsequent counts of flying young of the year at other colonies within the same group will be used to corroborate results from this method.